I will say as someone who uses microfuge tubes and freezer boxes on a daily basis for work (not just for daylilies) the 9x9 dividers are easier with the 1.5 mL tubes. The others don't leave enough room for the caps and end up being too crowded.
If you're really pressed for space there are smaller 0.5 mL tubes but I'm not sure if there are different dividers that will let you store more in a box.
